Machines for drilling upwardly, sometimes known as box hole machines, are often used in underground mining operations. In some instances the machine is used to rob ore material which then falls downwardly toward the machine. In other instances the machine is used to create a vertical communicating shaft that extends between two horizontal drifts or tunnels of the mine.
A communicating shaft must ordinarily, for safety reasons, be cased with a metal casing. It has been the practice in the past to first drill the vertical communicating shaft between the two horizontal drifts or tunnels, and then subsequently to install the metal casing within the shaft.
Some mining operations, however, are conducted in earthen material which is not supported adequately to be cut or mined in the usual manner. When drilling in this bad ground, the earthen material may flow into the shaft or hole before it can be cased. A difficult problem is then presented.
Thus, a problem known to mining operations of the prior art has been that sometimes it has not been possible to construct a cased shaft where one is desired, because the hole or shaft after it has been cut will become obstructed or clogged by the bad ground which flows into it.
The object of the invention, therefore, is to provide a method for drilling and casing a vertical hole in bad ground.